Spark-plug.



UNITED sTATEs PATENT oEEIoE.

HARRY R. KELSEY AND DALLAS B. BENHAM, OF MINNEAPOLIS, MINNESOTA.

SPARK-PLUG.

17 '0 all whom it may concern:

Be it known that we, HARRY It. KELsEY and DALLAS B. BENHAM, citizens of the United States, residents of Minneapolis, county of Hennepin, State of Minnesota, have invented certain new and useful Improvements in Spark-Plugs, ofwhich the,

* following is a specification.

The object of our invention is topr ovide 19.; a spark plu having a sparking surfaceof comparative y large area and a neutral member insuring the formation of a multiplicity of sparks and the ignition of the charge in the cylinder. A

A further object is to provide a plug 'having sparking surfaces which can be easily and quickly removed for cleaning or repairing.

Other objects of the invention will appear from the following detailed description.

The invention consists generally in various constructions and combinations, all as hereinafter described and particularly pointed out in the claims.

In the accompanying ,part of this specification, Figure l is an elevation of a spark plug embodying our invention,

i Fig. 2 is a vertical sectional view of the same,

Fig. 3 is a perspective view of the outer sleeve forming one of the electrodes,

Fig. 4 is a sectional view on the line 00-21: of Fig. 2.

In the drawing, 2 represents the metallic plug that is tapped into the wall of the cylinder in the usual way and seated on drawings forming the gasket 3. The plug is hollow, as usual in devices of this kind, and is. adapted to receive an insulating member a of porcelain or other suitable material. This member 4 has a collar 5 formed thereon and a shoulder 6 is provided in the plug 2 between which and the collar 5 suitable material, such as asbestos 7, is placed. The outer end of the plug is interiorly threaded to receive a nut 8 which is exteriorly threaded to engage the threads of the plug and is seated at its lower end against the collar 5 to clamp the member a securely against the shoulder 6.

Within this insulating member 4 is mounted an electrode bolt 9 projecting through the insulating material at each end and threaded at its outer end to receive the thumb nut 10, between which and the nut with the electrode electrode bolt.

Specification of Letters Patent, Patented Dc, 30 1919 Application filed February 7, 1916.

Serial No. 76,574.

11 the conductor of the electric'current is clamped. l/Vithin the open inner end of the plug 2 a sleeve is arranged, consisting of rings 12 and 13 connected with one another the inner surface of the plug, said-ring being divided transversely at 17 to permit it to be compressed or contracted suiiiciently to enter the open end of the plug and when 1t is inserted into the plug and released,

the ring will expand and engaging the walls of the recess, will be held temporarily therein, but may be easily and quickly removed by grasping the inner end of the sleeve.

The walls of the sleeve are in circuit with the cylinder through the metal plug, as

- usual in spark plugs, and the ring 12 has a circular sparking surface 18 concentric this sleeve removably mounted in the plug, but it may be formed as a continuation of the walls of the plug, if preferred. This, however, would be an obvious modification and I have not thought it necessary to illustrate it herein, as the change would merely consist in extending the threaded end of the plug to a point opposite the end of the A second sleeve 19 is provided, fitting within said first named sleeve and having 'anopen upper end adapted to receive the recessed end 20 of the insulating member 4:, and there is sufficient friction between the sleeve and the insulating member to hold the sleeve in place thereon. The lower end of the sleeve 19 is encircled by the sparking surface 18 of the outer sleeve and a narrow gap is formed between them. Said sleeve 19 has a ring 21 forming a sparking surface and provided with a central open. ing 22 into which the electrode bolt 9 projects, said bolt being spaced from the sur face of the ring a sufficient distance to insure the formation of a multiplicity of sparks between it and the ring 12 and thereby greatly increase the certainty of ignition of the charge in the cylinder.

We prefer to designate the sleeve 19 as the neutral. member of the plug, as it has an insulating bearing on the part 4 and its ring 21 partially bridges the gap between the electrode bolt and the surface 18 and provides for a large increase in the sparking olt 9. We have shown around them is provided for, will be entirely eliminated and the sparking surfaces w1ll remain remarkably clean under allcondi tions.

This plug is of extremely simple construction, the members having the sparking sur-.

faces are easily accessible, and can be readily removed for cleaning or repairing wit out disturbing the other connections of the plug. I

We claim as our invention y 1. A spark plug comprising a conducting member having means for mounting it in an therefrom, said neutral electrode belng en engine'cylinder, an insulating member fi ting wlthin sald conducting member, a pinshapedelectrode mounted in sald insulatlng member and projecting beyond the inner end 9 thereof, sleeves concentrically arranged and mounted respectively on said conducting member and said. insulating member, said sleeves being provided with annular sparking surfaces, the sparking surface of the inner sleeve encircling and being equi-distant substantially from the end of said electrode and the sparking-surface of said outer sleeve encircling the corresponding surface of said inner sleeve and being uniformly spaced from said sparking surface, whereby annular gaps are formed between said electrode and said inner sleeve and between said sleeves for evenly distributing the current and providing a multiplicity of sparks between said electrode and said surfaces, said sleeves having openings in their walls and the annular gaps between said sparking surfaces being unobstructed to allow the free circulation of the fuel gas between them.

2. A spark plug comprising 'a conducting member having means engine cylinder, an insulating member fitting within said conducting member, an electrode mounted in said insulating member and projecting beyond the inner end thereof and sleeves concentrically arranged and mounted respectively on 'said conducting between said therefrom,

air gaps-will be formed between said elecelectrodes.

' en glne cylinder,

said pin-shaped electrode,

for mounting it in an active and neutral electrodes.

member and said insulating member, said sleeves having annular, inwardly pro ect1ng ribs formed thereon, provided with sparka sleeve encircling the corresponding surface of said inner sleeve and being uniformly spaced sleeve, whereby annular gaps are formed electrode and said inner sleeve and between said sleeves for evenly distributing the current and providinga' multiplicity of-sparks between said electrode and said surfaces, a

3. A spark plug comprising a conducting from the outer walls of said innermember adapted for mounting it in an en; 7

gine cylindenan insulating member fitting therein, a pin-shaped electrode centrally mounted in said'insulating member, an active electrode" mounted in said conducting -member and having a sparking surface ena neutral I electrode having a sparklng surface encircircling' said pin-shaped electrode, cling said pin-shaped electrode and spaced circled by said active electrode and spaced whereby concentrically arranged trodes to provide a multiplicity of sparks, and said gaps being unobstructed for a free circulation of fuel gas through them and through and between. said active and neutral 4. A spark 'plug' comprising a conducting member adapted for mounting it ing an an insulating member ,fi ting therein, a pin-shaped electrode mount d in said insulating member, an active elec- I trode mounted in said conducting member and having a sparking surface encircling a neutral electrode having a sparking surface encircling said pin-shaped electrode and spaced therefrom, said neutral electrode being encircled by said active electrode and spaced there from, whereby air gaps will be formed be tween said electrodes to provide a multiplicity ofsparks, and said gaps being un obstructed for a free circulation of fuel gas through them and through and between said In witness whereof, we have hereunto set our hands this 3d. day of January 1916.

HARRY aKELsEY. DALLAS B. BENHAM, 

